Grease and process of making the same



50 water In proceeding according to the present inven Patented May 3, 1938 UNITED STATES GREASE AND PROCESS OF MAKING THE SAME James McKee, Media, Pa... assignor to Sun Oil Company, Philadelphia, Pin, acorporation of New Jersey No Drawing Application October 18, 19:2.

Serial No. ceases 16 Claims.

The present invention relates to a process for making grease and to the grease produced thereby.

In the production of lubricating greases it iscustomary to suspend certain substances in mixtures of soaps and oil and to effect such suspension by grinding the-desired substances into the grease in order to obtain as complete a mixture as possible. Notwithstanding the precautions m which are taken to obtain complete mixtures it frequently happens that hard particles are found in greases so prepared, which particles result in the scratching and abrasion of the metal surfaces to which the grease is applied.

It is an object of the present invention to provide a grease having a filling material incorporated therein so'efiectively that it will not separate on heating and subsequent cooling and to pro.-

vide a process for making such grease. Other objects will appear as the description progresses. In. carrying out the present invention any grease kettle provided with heating means may be used. In addition to the grease kettle it is'necessary to provide two containers for solutions to be used in the process.- These containers should be provided with piping connecting them with the grease kettle. As before stated, any known type of grease kettle may be used, but it is preferred that a grease kettle provided with a steam Jacket and agitating paddles be provided. Such a grease kettle is disclosed in my copending application Ser. No. 439,609 flied March 28, 1930. In manufacturing a batch of the present grease the following materials may be used in the proportions stated below, although the proportions given may be varied and equivalent materials substituted without departing from the spirit of the present invention and I do not wish to be limited in my claims to the specific proportions given;-

r Q Pounds Stearic or other substantially pure fatty acid 100 Tallow or other glyceride or mixture of glycarides e Petrolatum or asphaltic or paraflin base mineral oil having a viscosity approximating 150 seconds Saybolt at 210 F 200 Caustic sodain aqueous solution of 35 Be--- 42 Aluminum sulphate, dissolved in 20 gallons of tion the fatty acid, tallow or glyceride mixture, and petrolatum or oil are charged to the grease 55 kettle, gently heated and thoroughly agitated oleate and sodium palmitate.

until the entire mass is melted and in perfect solution. During the mixing and melting step it is necessary to exercise care to prevent the tallow or fatty acid from decomposing by overheating the same. When all of the ingredients are 5 thoroughly melted and in perfect solution with each other, the caustic sodasolution, which meanwhile has been prepared in one of the other containers, is run into the grease kettle, while agitation of the whole mass is continued, in order to saponify the stearic acid and tallow.

As soon as saponification has started, which fact may readily be determined by the formation of soap curds, the aluminum sulphate is slowly added to the saponifying mixture. As the aluminum sulphate is being slowly added the kettle is further heated, either by flame, superheated steam or other heating medium, to a temperature approximating 375 to 425 F. and the mass is constantly and vigorously agitated. The heating and agitation is continued, the time being so gauged as to insure the removal, by vaporization, of the water added with the caustic soda and aluminum sulphate and the water formed by the saponification reaction. One of the objects of the invention is to produce a grease which is as free from moisture as possible. After the removal of the contained water the preparation of the grease is completed and the batch may be permitted to cool partially and drawn off into suitable containers for shipment and sale. The grease may be used just as it is drained from the kettle or it may have any desired quantity of oil added to it in order to bring it to any required consistency. v

The reactions which occur during the present process are as follows: The tallow, which is composed of stearin, olein and palmltin, and'the stearic acid. react with the caustic soda to form the sodium soaps of stearic, 4o oleic and palmitic acids, glycerin and water. The soaps so formed are sodium stearate, sodium The subsequent additionof aluminum sulphate to the above mixture of sodium soaps, glycerin, oil and water 5 causes a partial transposition of the sodium soaps to aluminum soaps of the same acids and as a consequence throws out sodium sulphate in an extremely finely divided condition, which sodium sulphate is believed to be colloidally dispersed within the grease. Due to the high temperature to which the mixture of sodium soaps, aluminum soaps, giycerine and sodium sulphate is subjected to (375-425 F, or higher if necessary) the aluminum soaps are decomposed to the ketones:

stearone, palmitone and olcone, and to'aluminum compounds.

The amount of caustic soda added is in excess of that necessary to completely saponify the free fatty acid and tallow present, but the excess is aluminum hydroxide or sodium aluminate or it may be adsorbed by various aluminum compounds formed by the partial decomposition of the aluminum soaps.

The final product consists of the ketones of palmitic, oleic and stearic acids; the sodium soaps of the same acids; glycerin; anhydrous sodium sulphate; and aluminum compounds which are probably the hydroxide and one or more oxides or aluminates.

Stearic, oleic, or pahnitic acids alone, when reacted with caustic soda, and the resulting soaps partially transposed to aluminum soaps by the addition of aluminum sulphate, will not produce a product having the desired properties with regard to solubility or dispersibility in oil, or having the desired consistency and colloidal properties which are characteristic of the product produced by the present process.

It is believed that the small amount of glycerine produced by the saponification of the tallow and the presence of the above mentioned ketones together with aluminum hydroxide may account for the desirable colloidal and other properties characteristic of the herein described composition.

So far as physical qualities are concerned the present grease is well suited for all types of lubrication where grease is used. The present improved grease combines the desirable qualities of the sodium and lime greases as well as the aluminum greases. It is a non-crystalline, pseudo-colloidal, gelatinous grease which, when anhydrous. is soft, non-elastic and smooth, as distinguished from many greases which are fibrous in texture. The present grease also has great spreading properties and is free from any abrasive matter. Further, the present grease, when anhydrous, is neutral and is insoluble in water or absolute alcohol but is capable of colloidal dispersal in mineral oils in any proportion. It is further characterized by having a melting point of 375 to 425 F. as compared with 200 to 210 F, for calcium or aluminum greases. It is also to be noted that the addition of a mineral oil to the grease to produce a grease of lower consistency does not lower the melting point.

While certain materials have been specified and certain proportions given in the specific example it is apparent that equivalent materials may be substituted and the proportions altered without departing from the spirit and scope of the present invention.

Having now described my invention what I claim and desire to protect by Letters Patent is:

1. The process of making a grease comprising mixing a fatty acid, glycerides and petroleum hydrocarbons, forming soaps from thie'fatty acid and glycerides by the addition of alkali in excess of the quantity required for saponification, but before saponification is complete causing a partial transposition of the soaps, to aluminum soaps by the addition of an inorganic aluminum salt, and then decomposing the aluminum soaps by heating to form a colloidal dispersal of reaction products containing aluminum in the petroleum hydrocarbons.

2. The process of making a grease comprising mixing a fatty. acid, glycerides-and petroleum hydrocarbons. forming soaps from the fatty acid and glycerides by the addition of caustic soda in excess of the quantity required for saponification, but before saponification is complete causing a partial transposition of the soaps to aluminum soaps by the addition of aluminum sulphate, and then decomposing the aluminum soaps by heating to form a colloidal dispersal of reaction products containing aluminum in the petroleum hydrocarbons.

3. The process of making a grease comprising mixing a fatty acid, glycerides and petroleum hydrocarbons, adding thereto'an alkaliin aqueous solution in excess of the amount necessary to saponify the available saponiflable material, then before saponification is complete adding an aqueous solution of an inorganic aluminum salt to cause formation of aluminum soaps, and then heating the mixture to a temperature suilicient to decompose the aluminum soaps to form ketones.

4. The process of making a grease comprising mixing a fatty acid, glycerides and petroleum hydrocarbons, adding thereto caustic soda in aqueous solution in excess of the amount necessary to saponify the available saponiiiable material, then before saponification is complete adding an aqueous solution of aluminum sulphate to cause formation of aluminum soaps, and then heating the mixture to a temperature suflicient to decompose the aluminum soaps to form ketones.

5. The process of making a grease comprising reacting an excess of caustic soda in aqueous solution with a mixture of a fatty acid, glycerides and petroleum hydrocarbons to form sodium soaps and glycerin; partially transposing such sodium soaps, by the addition of an aqueous solution of aluminum sulphate, to aluminum soaps, -such transposition being accompanied by the formation of sodium sulphate in pseudo-colloidal form; and heating the mixture to such temperature as will partially decompose the aluminum soaps to form a colloidal dispersal of the soaps, glycerine, sodium sulphate and products of partially decomposed soaps in the petroleum hydrocarbons.

6. The process of making a grease comprising melting 200 parts of a mixture of a fatty acid and a fixed fat, together with petroleum hydrocarbons, adding to such mixture not less than 34 nor more than 45 parts of caustic soda in aqueous solution, then before saponification is complete adding to the saponifying mixture not less than 50 nor more than 60 parts of aluminum sulphate in aqueous solution, and during said last step heating the mixture to 375 to about 425 F. to evaporate contained water and decompose the aluminum soaps.

'7. The process of making a grease comprising melting together 100 parts of stearic acid, 100 parts of a fixed fat and 200 parts of petroleum hydrocarbons, adding to such mixture not less than 34 nor more than 45 parts of caustic soda in aqueous solution, then before saponification is complete adding to the saponifying mixture not less than 50 nor more than 60 parts of aluminum sulphate in aqueous solution,

and during said last step heating the mixture to about 375 to 425 F. to evaporate contained water and decompose the aluminum soaps.

8. A lubricant comprising a mixture of sodium fatty acid soaps and heat decomposition products of aluminum fatty acid soaps, colloidally dispersed in petroleum hydrocarbons.

9. A lubricating grease having a melting point of 300 to 325 F. and comprising a mixture of sodium fatty acid soaps, sodium sulphate, ketones derived from higher soap-forming fatty acids, and petroleum hydrocarbons, said grease being characterized by the fact that it is insoluble in Water and alcohol.

10. A lubricant comprising a mixture of sodium fatty acid soaps, glycerine, sodium sulphate and ketones derived from higher soap-forming fatty acids, colloidally dispersed in petroleum hydrocarbons and characterized by the fact that it is insoluble in water and alcohol.

11. A lubricant comprising a mixture of sodium fatty acid soaps, glycerine, sodium sulphate and decomposition products produced by heating aluminum fatty acid soaps, colloidally dispersed in petroleum hydrocarbons and characterized by the fact that it is insoluble in water and alcohol.

12. A lubricating grease having a melting point of 300 to 325 F. and comprising'a mixture of sodium fatty acid soaps, sodium sulphate, ketones derived from higher soap-forming fatty acids, and

petroleum hydrocarbons, said grease being miscible with mineral oil to alter its consistency and characterized by the fact that it is insoluble in water and alcohol.

'13. A grease composition comprising a colloida1 dispersal of sodium fatty acid soaps, ketones' derived from higher soap-forming fatty acids, and sodium sulphate in petroleum hydrocarbons.

14. A grease compositionv comprising a colloidal dispersal of sodium fatty acid soaps, ketones derived from higher soap-forming fatty acids, sodium sulphate and inorganic aluminum compounds in petroleum hydrocarbons.

15. The process of making a grease comprising melting a mixture of a soap-forming fatty acid and a fixed fat together with petroleum hydrocarbons, adding to such mixture caustic soda in aqueous solution, then before saponification is complete adding to the mixture an aluminum salt in aqueous solution, and during said last step heating the mixture to evaporate contained water and decompose aluminum soaps.

16. The process of making a grease comprising mixing a soap-forming fatty acid, glycerides and petroleum hydrocarbons, adding an alkali capable of forming soaps with the fatty acid and glycerides, then'adding an altuninum salt, and heating to produce a decomposition of aluminum soaps so formed.

JAB/MS MOKEE. 

